航空座椅零部件等温锻造工艺及模具设计

利用DEFORM-3D有限元软件数模拟技术对航空座椅零部件工艺参数和等温锻造模具进行设计。建立有限元模型,采用DEFORM-3D有限元软件对其成形过程进行数值模拟,分析了锻造温度和锻造速度对锻造力的影响,并从模具寿命方面考虑设计了模具预热温度等成形工艺参数。结果表明,采用等温锻造模具在40MN液压机上能够生产出合格的航空座椅零部件工件;毛坯加热温度为370℃～390℃,模具预热温度为370℃～390℃,锻压速度为1.0 mm/s,锻造性能较好,符合设计要求。     

石油钻杆接头模锻工艺研究

介绍了石油钻杆接头采用自由锻造的工艺方式存在毛坯余量大、材料利用率低、生产成本较高等缺点.为了提高钻杆接头毛坯精化程度和降低生产成本,提高市场竞争力,需要更高效的加工方式.通过对钻杆接头模锻工艺参数摸索,合理地选择了钢坯感应加热、毛坯加工率、加工设备选择、模具设计、锻后缓冷等工序工艺参数,最终实现了钻杆接头一次模锻成形的工艺.石油钻杆接头模锻后,降低了毛坯的下料质量,减少了机械加工余量,提高了材料利用率,降低了生产成本.     

气门座圈粉末锻造工艺的数值模拟与实验

目的研究气门座圈的粉末锻造工艺,提高产品的致密度。方法通过建立气门座圈粉末锻造数值模型,分析锻造过程中相对密度的变化过程,研究预制毛坯初始相对密度、锻造加热温度和成形速度对致密化的影响。在此基础上进行粉末锻造实验,并与模拟结果比较。结果随着预制毛坯初始致密度、加热温度的增加以及成形速度的降低,粉末锻造致密度化所需的成形力降低;预制坯初始密度对锻件密度均匀性影响最为显著。经过粉末锻造后的气门座圈,密度从6.6 g/cm~3提高到7.46 g/cm~3,致密度达到96.4%。结论相比传统压制-烧结工艺,粉末锻造可以大幅度提高气门座圈的致密度。     

支承架数值模拟应用

利用Pro/e对毛坯、模具进行三维造型,利用模拟软件DEFORM-3D对支承架等温锻造成形过程进行数值模拟,得到成形过程中锻件的填充情况以及成形载荷、应变场和应力场的场量分布。通过对比实际零件生产情况再次证明了该软件模拟的可行性及有效性。基于模拟结果,对锻造缺陷的成因进行了初步分析,并提出了成形工艺及模具设计的改进建议。     

高功率密度发动机连杆热模锻工艺模拟与优化

目的研究某高功率密度发动机连杆的锻造工艺。方法首先采用传统设计方法设计了连杆模锻工艺,再通过有限元模拟分析优化工艺。结果根据有限元模型,分析了传统设计方法下的毛坯充型效果,直观地再现了终锻成形过程中的坯料外形演变和容易出现成形缺陷,在此基础上,优化了毛坯尺寸,满足了终锻充型要求。结论通过工艺试验进一步验证了模拟结果,获得的锻件没有出现缺肉、折叠等缺陷,微观组织较均匀,能够满足技术要求。     

航空接头锻件等温锻压成形工艺

为了提高航空锻件的综合性能,通过等温锻压工艺研究了航空接头锻件的成形过程,采用Deform3D有限元软件对高筋薄壁铝合金航空接头锻件的锻压成形工艺进行了仿真研究,在实验室油压机上开展了缩比(1∶5)锻件的成形工艺实验.研究结果表明:在坯料与模具温度均为450℃、成形速度为0.1 mm/s的等温模锻工艺下,材料变形抗力比常规热模锻降低70%,材料在模腔中的流动性提高,锻件充填完好,锻件变形均匀,应力集中降低;等温锻造工艺可使锻件获得流线顺畅、晶粒细小、力学性能优良的纤维组织,避免了热模锻易出现的涡流、折叠、穿流、充填不满等锻造缺陷;仿真与实验结果吻合,为航空接头锻件锻压成形工艺的制订提供了依据.     

叶片精密锻造过程数值模拟技术研究进展

介绍了叶片精锻成形的三维有限元数值模拟的过程,以及固体型塑性有限元法和流动型塑性有限元法的特点,针对近年来叶片精锻成形的三维有限元数值模拟技术对工艺参数及微观组织演化进行模拟的现状,进行了详细论述,在此基础上,提出了叶片精密锻造的三维有限元数值模拟技术未来发展的方向。     

锥管径向锻造数值模拟及参数优化

本文以锥管为研究对象，以防锈铝合金冷轧管坯LF2M为锥管材料，对其径向锻造成形工艺及参数优化进行研究。利用ABAQUS软件建立锥管三维有限元数值模拟模型，采用正交试验法对成形过程中的关键参数（轴向送进量、旋转角度、摩擦因数）进行优化。以锥管壁厚最大值到未成形端曲线残差平方和的平均值的最小值为优化目标，获得最佳工艺参数，实验结果与模拟结果吻合良好。     

曲轴模锻成形工艺分析及模具优化

采用有限元方法对曲轴锻造成形工艺过程进行数值模拟,主要分析不同的飞边槽结构对曲轴预锻成形中坯料的充填情况及成形载荷的影响。根据模拟结果可知,在飞边槽桥部合理增设阻力沟或阻力墙,将对曲轴平衡块的充填性有很大程度的改善,并优化了毛坯尺寸。     

锻造比对身管膛线成形影响分析

目的膛线是身管的关键部位,其主要作用是使弹头旋转运动,以保持弹头飞离膛口后稳定飞行。膛线成形性的状况对枪管的初速、精度都有重要的影响,故需要分析径向锻造过程中不同锻造比对身管膛线成形性的影响。方法使用有限元商业软件Abaqus建立三维有限元模型,对身管膛线的成形过程进行数值模拟,得出不同锻造比对身管膛线成形影响的规律。结果锻造比大于35%时,阴线的边界处的Mises应力大于材料的强度极限,膛线因应力过大而扭曲;锻造比小于15%时,阳线上的菱角处成形不充分,膛线的阴、阳线边界不分明;当锻造比为25%时,膛线应力分布在合理范围内且成形良好。结论通过仿真得出新材料的合理锻造比范围在25%左右,在15%~35%之间。     

轮毂轴管终锻成形模拟研究

根据某规格汽车轮毂轴管零件的形状尺寸特点,设计了预锻毛坯和2种终锻成形方案,并对所制定的2种终锻方案进行了工艺和模拟分析。2种方案的模拟结果显示,顺序成形过程稳定,变形只局限于端部;一次镦粗变形不局限于变形的端部,在变形结束时有少量金属流入杆部,这将会使端部缺料和杆部出现折叠和缩径缺陷。顺序成形可改善模具的受力状况,成形力有所降低,提高了模具寿命。根据力-行程曲线,应严格控制变形部位金属的体积,实现小飞边精密锻造,避免成形力在成形最后阶段急剧增大,以致损坏模具和设备。     

Numerical and experimental investigation of cold rotary forging of a 20CrMnTi alloy spur bevel gear

Due to the complex three-dimensional (3D) geometry and tooling design, mass production of precision spur bevel gears by machining or conventional forging technology is impeded by numerous stubborn barriers to date. Cold rotary forging, an innovative incremental metal forming process, has great potential to improve the current situation owing to its flexibility and low tool load requirement. In the present study, a sound 3D rigid-plastic finite element (FE) model of cold rotary forging of a 20CrMnTi alloy spur bevel gear is developed under the DEFORM-3D platform. To ensure the precision of the proposed FE model, a series of experiments are well performed for the identification of the mechanical properties of 20CrMnTi alloy and the realistic friction conditions prevailing at the die-workpiece interface. By utilising this FE model, the workpiece geometry is optimised with the intention of achieving a better filling of gear shape and a lower forming load requirement, and then the distribution of different field-variables such as flow velocity and effective strain are thoroughly investigated. For verification purposes, the cold rotary forging experiments of 20CrMnTi alloy spur bevel gears are subsequently conducted. Good agreement between the experimental results and the simulation ones is highlighted by comparing the gear shape after cold rotary forging and the axial forging force, which validates employed model.     

阀盖模锻成形模拟分析与试验验证

目的 某型号不锈钢阀盖是一种典型的长肋条内空型零件,在模锻制造过程中,阀盖锻件容易出现不同程度的折叠和裂纹缺陷,亟需改进成形工艺以提升合格率.方法 采用有限元方法分析坯料在制坯/预锻/终锻全流程的金属流动规律和终锻件成形质量,得到最佳成形工艺方案.结果 方坯在后续成形时易产生横向流动,且局部充型不饱满;六边型坯在预成形和终成形时流动均匀、横向流动小,且有效抑制了充型不饱满缺陷;预制坯在过渡区长度过短,产生了折叠缺陷;采用六边形坯料和增加过渡区长度可以获得无缺陷阀体锻件.结论 采用新工艺制备的阀盖锻件合格率达到了100％,通过全流程工艺分析,能够得到金属流线规律,进而优化模锻成形方案,改善成形质量.     

带径向扭曲叶片转子精密塑性成形技术的研究

设计了一套带有组合凹模的等温闭塞式成形试验模具，利用模拟试验方法研究了模具形状、坯料形状和成形力等对金属变性流动规律的影响。研究结果表明；采用等温成形和闭塞式成形复合技术可以整体精密成形带径向扭曲叶片的转子锻件；利用组合凹模结构能够解决转子锻后的顺利脱模问题，等温变形条件使薄而长的铝合金叶片的成形性大大提高，而锥底凸模和分流原理可以有效地降低模压力和提高金属充填模腔能力，所成形的锻件的叶片部分接近零件的形状和尺寸，金属的流线方向完全沿零件的几何外形分布，可以有效地提高构件的强度。     

A Study of One-Step-Gradual Forging Process with the Progressive Heating Method

A resistance heating method and a one-step-gradual forging process were used to study a billet within a die. The billet was directly heated accompanied with a progressive heating manner. The pressing speed of the upper die is kept at the same course with the billet heating speed, thus integrating the forming procedure by simply controlling one speed in effect. Experimentally, it is found that based on this innovative forming method, the experimental results indicated that the billet can be heated to 1000°C from top to bottom within approximately 5 s. This leads to a further modification of the material flow for a 12-point bolt-head, which in the end results in an improvement of the forming ability. Most importantly, the forming load of gradually forging can cause a 25% deduction compared with the one performed by one-step forging. Numerically, the commercial finite element method package of DEFORM was used to simulate the novel one-step-gradual forging process. The simulated material flow phenomena were thoroughly studied in subsequence. The results between FEM simulations and experiments showed good agreements.     

电液锤上GH901合金涡轮盘模锻成形工艺

目的 研究GH901合金涡轮盘锻件的成形工艺.方法 采用有限元软件Simufact-2D对镍基高温合金涡轮盘的锤上模锻过程进行数值模拟分析,研究不同中间坯高径比下涡轮盘的填充效果及等效应变变化规律;研究不同锤击能量下涡轮盘的温度分布规律.结果 GH901合金涡轮盘锤上模锻时,中间坯高径比过大或过小均影响填充效果,同时不...     

浮动凹模温精密成形圆柱斜齿轮变形规律分析

目的研究采用浮动凹模工艺温精密成形圆柱斜齿轮时,不同凹模运动速度下齿轮力能参数和各种场量变化规律。方法结合浮动凹模原理和圆柱斜齿轮结构特点,利用Defrom-3D软件建立变形-传热耦合有限元模型,模拟圆柱斜齿轮采用浮动凹模温精密成形过程,分析不同凹模运动速度下的变形规律。结果通过模拟分析,得到了凹模运动速度不同时的温成形斜齿轮成形载荷特点、坯料流动速度场分布、等效应力-应变分布、温度场分布等规律。结论采用浮动凹模工艺成形圆柱斜齿轮,可以减小成形力,当凹模运动速度大于凸模下行速度时,齿轮成形性更好。     

Influence of the forming angle in cross wedge rolling on the multi-directional forging of crankshafts

In each industrial process for the production of crankshafts a low energy demand and a fast processing time are required. Crankshafts have a very complex geometry and are forged with a high percentage of flash compared to other forging parts. Recent research showed the feasibility of a flashless forging of crankshafts. One way to forge a flashless crankshaft within three steps is to use cross wedge rolling, multi-directional forging and final forging. This paper presents the investigation results regarding the influence of the forming angle α in cross wedge rolling on different parameters at multi-directional forging. First, the state of the art is presented. As a basis for the investigations the process development and tool design of cross wedge rolling and multi-directional forging are described. Afterwards the paper’s results regarding the influence of the forming angle α on flash generation, billet temperatures, forming degree, forming forces and effective strain will be presented as a parameter study. Generally, flash is generated because a rotation-symmetric billet is forced into an asymmetric movement. The influence of an increasing forming angle leads to a higher amount of flash at the bottom of the crankwebs.     

3D coupled thermo-mechanical FE analysis of roll size effects on the radial–axial ring rolling process

Radial–axial ring rolling is an advanced but complicated incremental metal forming technique with multi-factors coupling interactive effects. During the radial–axial ring rolling process, the deformation and thermal behaviors of the ring mainly occur in the roll passes which are constituted by rolls. So, the rolls sizes have enormous influence on the quality of the rolled ring as well as the stability of the process. In this paper, the ranges of rolls sizes and forming parameters are reasonably determined at first, then a 3D elastic–plastic and coupled thermo-mechanical FE model of radial–axial ring rolling is developed using the dynamic explicit code ABAQUS/Explicit, and its reliability is verified theoretically and experimentally. Based on the valid 3D FE model, the size effects of rolls on the radial–axial ring rolling process are investigated. The research results provide valuable guidelines for the design and optimization of the rolls sizes in the actual radial–axial ring rolling production.